1. Field of the Invention
The present invention relates to a method for controlling a gas turbine, and more particularly, to a method for controlling a gas turbine by which the gas turbine can maintain a target torque set by a user.
2. Description of the Related Art
In general, a gas turbine consists of a gas turbine engine, a fuel pump which supplies fuel to the gas turbine engine, and a motor which drives the fuel pump. A control system of the gas turbine controls torque of the motor which drives the fuel pump or opening of the fuel valve so that the gas turbine engine can maintain a set torque.
A conventional gas turbine control method is as follows. First, the difference between a target torque set by a user and an actual torque of a gas turbine engine is obtained. A typical proportional-integral-differential control is performed according to the obtained torque difference and thus a subject of the control, i.e., a control signal for driving a motor for a fuel pump or a fuel valve. However, the typical proportional-integral-differential control method has a limit in controlling a gas turbine whose input/output properties are not easily identified.
A fuzzy control method has been suggested to overcome the limitation of the above typical proportional-integral-differential control method. However, the fuzzy control method also shows a limitation in controlling a gas turbine in which the phase of an actual torque signal changes very rapidly.
Accordingly, accuracy, precision and stability are required in controlling a gas turbine in which the input/output properties thereof are difficult to define and a torque signal thereof has a very rapidly changing phase.